1. Field of the Invention
The instant invention relates generally to a lubrication system for an idler roll set, and more particularly to unique means for interconnecting flexible lubrication tubes between end caps secured on the hollow support shafts for adjacent idler rolls.
2. Prior Art
Numerous attempts have been made to achieve a one-shot lubrication system which will effectively lubricate the whole series of a set of idler rolls when a pressurized grease gun has been applied to a fitting at one end of the series and a suitable pressure relief valve or fitting has been applied to the opposite end. In addition to having the ability to effectively distribute the lubricant, the system must be flexible in nature to permit the axial angularity of the adjacent rolls to be altered without impairing the effectiveness of the system by destroying the communication between adjacent rolls.
One approach for realizing these objectives was set forth in U.S. Pat. No. 3,070,219, granted Dec. 25, 1962, to Vincent J. Donadio. Such patent proposed ball and socket joints of hollow construction defined between adjacent idler rolls to communicate with hollow axial shafts defined within the rolls, thus forming a lubricant passageway extending along the full length of the series of rolls. Radial ports in the lubricant passageway permit limited quantities of the grease to flow outwardly and lubricate the bearings situated at the opposite ends of the shaft for each roll.
Another approach for realizing these objectives was set forth in U.S. Pat. No. 3,334,727, granted Aug. 8, 1967 to John D. Rieser. Such patent proposed a unitary rigid tubular shaft that supports an entire set of rolls, such shaft having a substantially horizontal central portion and at least two angularly bent end portions that define a concave surface for the conveyor belt passing therealong. A spaced series of anti-friction bearings are mounted on the shaft, and spaced brackets maintain the angular relationship between adjacent rolls. Plugs are situated in the shaft at spaced intervals to divert the flow of lubricant issuing from radial ports in the shaft into, and through, the anti-friction bearings, and thence back into the tubular shaft.
Yet another approach was set forth in U.S. Pat. No. 3,259,227, granted July 5, 1966 to Walter C. Steinmetz, and in U.S. Pat. No. 3,489,471, granted Jan. 13, 1970 to Hugh D. Kelley. These patents proposed a cylindrical tube that is retained at its opposite ends in apertures in end caps secured to the opposing ends of axial shafts of adjacent rolls. The cylindrical tube is slipped into position within the apertures in the end caps and extends axially into the hollow bores extending through the rolls. The tube is slidable within the axial bores as the rolls are angularly adjusted relative to one another, thus avoiding harmful stresses upon the tube. Radial ports communicating with axial bores in the shafts supporting the rolls permit the lubricant to flow into, and through, spaced bearings situated at the ends of each roll.
All of these approaches suffered from one or more defects. For example, the ball and socket joint of Donadio was expensive to machine and difficult to maintain in proper alignment and/or sealing relationship, whereas the single shaft of Rieser lacked the flexibility necessary to permit repeated adjustment of the angular relationship between adjacent rolls. The lubrication tubes proposed by Steinmetz and Kelley were not firmly secured in passageways in the end cap, and thus could work free from the passageway in the end caps under the severe operating conditions normally associated with troughing conveyors and the pressure of the lubricant being forced through the tubes.